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The [(C 2 H 5 )NH 3 ] 2 ZnCl 4 hybrid material was prepared and their calorimetric study and electric properties were investigated at low temperature. Indeed, the X-ray powder diffraction confirms the purity of the synthesized compound and the differential scanning calorimetric show several phase transitions at 231 K, 234 K, 237 K, 247 K and 312 K, which are proven by the variation of σ p and σ dc as a function of temperature. The equivalent circuit based on the Z-View-software was proposed and the conduction mechanisms were determined. The alternative current (ac) electrical conduction in [(C 2 H 5 )NH 3 ] 2 ZnCl 4 is studied by two processes that can be attributed to a hopping transport mechanism. These processes are the correlated barrier hopping (CBH) model in regions I and IV and the overlapping large-polaron tunneling (OLPT) model in region III. The optical study was also investigated by UV–vis absorption. In fact, the insulating behaviour of the material is established by Tauc plot obtaining a large value of indirect optical band gap energy.

The [(C2H5)NH3]2CuCl4 compound was prepared and characterized by several technique: the X-ray powder diffraction confirms the purity of the synthetized compound, the differential scanning calorimetric show several phase transitions at 236 K, 330 K, 357 K and 371 K, the dialectical properties confirms the ferroelectric–paraelectric phase transition at 238 K, which is reported by V. Kapustianyk et al. (2007) [1]. The two semi-circles observed in the complex impedance identify the presence of the grain interior and grain boundary contributions to the electrical response in this material. The equivalent circuit is modeled by a combination series of two parallel RP–CPE circuits. The temperature dependence of the alternative current conductivity (σg) and direct current conductivity (σdc) confirm the observed transitions in the calorimetric study. The (AC) electrical conduction in [(C2H5)NH3]2CuCl4 was studied by two processes that can be attributed to a hopping transport mechanism: the non-overlapping small polaron tunneling (NSPT) model in phase III and the correlated barrier hopping (CBH) model in phases I, II, IV, V and VI.

The [(C 2 H 5 )NH 3 ] 2 CdCl 4 hybrid material was prepared and its calorimetric study and electric properties were investigated at low temperature. The X-ray powder diffractogram has shown that the compound is crystallized in the orthorhombic system with Abma space group, and the refined unit cell parameters are a =7.546 A, b =7.443 A, and c =21.831 A. The calorimetric study has revealed two endothermic peaks at 216 K and 357 K, which are confirmed by the variation of f p and σ dc as a function of temperature. The equivalent circuit based on the Z-View-software was proposed and the conduction mechanisms were determined. The obtained results have been discussed in terms of the correlated barrier hopping model (CBH) in phase I (low temperature (OLT)), non-overlapping small polaron tunneling model (NSPT) in phase II (room temperature (ORT)) and the overlapping large polaron tunneling model in phase III (high temperature (OHT)). The density of localized states N F ( E ) at the Fermi level and the binding energy W m were calculated. The variation of the dielectric loss log( e ʺ) with log( ω ) was found to follow the empirical law, e ″= B ω m ( T ) .